Fuel System Internal Leaks

Connect a fuel pressure gauge to test port. Start engine and idle for approximately one minute. Turn engine off and observe fuel pressure gauge. Fuel pressure should be more than 44 psi (3 bar). After 30 minutes, fuel pressure should be more than 36 psi (2.5 bar). If fuel pressure quickly drops off, possible cause is faulty check valve at fuel pump. Repair or replace as necessary. If fuel pressure slowly drops off to less than specification, possible cause is leaking fuel injector(s) or faulty fuel pressure regulator. Repair or replace as necessary.